Interlock system



June 1943- G. 1.; CLAYBOURN EIAL 2,320,349v

INTERLOCK SYSTEM Filed Feb. 26, 1941 ybourvz E Zack.

INVENTORS an L. 674

a grdLla E. F w ///////A Patented June 1, 1943 INTERLOCK SYSTEM Glen L. Claybourn, Wilkinsburg, and Lloyd E.

Keck, Pittsburgh, Pa., assignors to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsyl- Vania Application February 26, 1941, Serial No. 380,648

' (c1. ro zcs) 11 Claims.

Our invention relates, generally, to interlocks, and has reference, in particular, to a mechanical interlock system for a plurality of doors disposed to be operated in 'a predetermined sequence, such, for example, as the multiple swinging doors or covers on metal enclosed switchgear or other metal enclosures for high voltage equipment.

Generally stated, it is an object of our invention to provide a mechanical interlock system for a plurality of enclosure doors that is simple and inexpensive to manufacture and install and which is positive and reliable in operation.

More specifically it is an object of our invention to provide for mechanically interlocking a plurality of doors with a master door so that the master door cannot be closed until all the other doors are closed, and none of the other doors can be opened until the master door, which may be provided with a separate lock device, is opened.

A further object of the invention is to provide for interlocking a plurality of doors of a switchgear enclosure with a master door so that only a single lock device on the master door is required for securing all of the doors in a closed position. 3

Yet another object of our invention is to provide for utilizing an interlock mechanism to prevent the closure -of a master door of a switchgear enclosure until a plurality of sub-enclosure doors thereof are in the closed position.

. Still another object of the invention is to provide for simultaneously actuating the. latch members of a plurality of enclosure doors in response to closure of a master door only when the plurality of doors are in predetermined positions.

Other objects will, in part, be obvious and will, in part, be explained hereinafter.

In accordance with our invention, a plurality of sub-enclosule doors positioned in side-by-side relation with a master door may be mechanically interlocked therewith by utilizing a latch mechanism including a plurality of pivotally connected latch bars slidably supported by the enclosure frame adjacent the associated doors for actuating locking pins to lock the said associated doors. Depending stop members on the latch bars lock the latch bars in the open position and projecting keepers with which the lock pins interfere when the associated doors are in closed position are arranged to lift their respective latch bars when the doors are closed, so that the stop members are rendered ineffective to prevent movement of the latch bars to the closed position. The latch bars are operatively connected to the mas- .ter door "by means of a connectorbar and a projectingstopon the master door sothat the master door cannot be closed untilall of the associated'sub-enclosuredoors are closed, and closure of the master door then actuates the latch bar to lock the associated sub-enclosure doors in the closed positionr The master door may then be locked by means of any suitable lock device. I

For a I more complete understanding of the nature and scope of our invention, reference may be had to the accompanying drawing, in which: Figure 1 is a-partly sectioned front elevational view from within a switching enclosure illustrating an interlock system embodying the principal features of the invention with the doors of the enclosure shownin the open position;

Fig. 2 is a sectional view taken along the line II--II of Fig. l with the doors in the closed position; v

Fig. 3 is an enlarged sectional view of the latch mechanism taken along the line III-III of Fig. 2;

Fig. 4 is an enlarged sectional view of-the latch mechanism of Fig. 3 in the semi open position;

Fig. 5 is an enlarged sectional view of the latch mechanism taken along the line V-V of Fig. 1; I

Fig. 6 is an enlarged sectional view of the latch mechanism of Fig. 5 in the closed-position; and

Fig, 7 is an enlarged partial View of the section shown in Fig. 2, with the master door in the open position.

Referring to Figs. 1 and 2 of the drawing, the reference numeral it may denote, generally, -a switchgear enclosure of a'type Well knownin the art having, for example, a plurality of separate compartments I2, I 3 and I4 provided with hinged doors l5, l6 and I8, respectively. jv

The door l8; which; will hereinafter be referred to asthe master door, may be provided with a hinge pin I9 about which it pivots, and-any suitable lockdevice, such as, for example, a keyoperated lock device 20 operated'bymeans of a key 2| normally contained in a lock onother switchgear apparatus (not shown), with theoperation'of which the master door ls'and the doors l5 and iii, hereinafter referred .to as sub-doors,

are to be interlocked. For eX'a-mplait may be desirableunder certain conditions to retain the key 2| of the lock device. 2% in. a similar lock device on a circuit breaker. (not-shown) so that t lq y. mayxnottbe removed therefrom to operate the locktdevicel 28 until the circuit breaker is in the open position, and'preventthe opening of the sub-doors i5. and l6,which may also contain'switching apparatus connected with the said circuit br'eakenuntil the master door I 8 has been opened. In order to efiect these results, the subdoors l5 and. i6 may be each provided with suitable lock or latchmechanisms 22 disposed to be operated. collectively in responseto movement of the master" door I8 by :a common actuating means24."-- i Sincethe latch mechanisms for anynumber of subdoors may be substantially the same, .it has been deemed necessary to describe only one of them in detail, and similar parts of the latch mechanisms for other sub-doors are identified by corresponding reference numerals. The subdoor I6, for example, maybe locked by a latch bar 26 slidably supported on the :framemembers 21 of the switchgear compartment; in openings'it therein and in the partitions .29 Joy means .of the bracket member 30. The bracket member '30 may comprise a c-shaped body member having a substantially straight centerportion 3 I which is considerably longer than the width ofthe latch bar 26 so as to permit it to be raised and lowered therein, and-inturned end portions 32, which'may be secured to the vertical frame member 21 -of the compartment in any suitable manner, such as by means of-welding. A lock-pin-33 may be securedto the latch bar 26 by means of a depending support member 34 so as to be movable with the latch bar. With a viewto retaining the latch bar 26in the open position a suitable stop member may be provided such as, for example, the

downwardly extendingend'portion 36 of the lock pin support 3 whichmaybe disposed to interfere-With thelower inturned end portion 32-of the bracket 30 when-thelatchbaris in the open position, as-shown in Figs. 1 and 5.

The lock pin 33---is disposed to interfere with suitable-means on the sub-door l6 when the door is closed and the lockpin is actuated to the closed position. For example, -a projecting keeper 38 may-beprovided on thedoor adjacent the lock pin a-ndprovidedwith a-nopening 3B-therein for receivingthe lockpin=33-when itis actuated to the closed or lockedposition.

lower inturned end portion 32 of the support bracket 30.

In order to interlock-the operation of the latch bar 26 with the operation of the master-door I8, the operating-means 24 may,-for example, comprise an elongated connector 42 slidably supportedon the vertical frame members 21 of the compartment M in anysuitable-manner, such .as

by meansof the rollers 43 secured to the frame members by means of'bolts 44. The spring 45 may be provided for normally urging the connector to the open position, and an operating connectionwith the door l8 may :be effected by the projecting lug 41 .on the master door, which may engage a depending stop 48 on the connector. .The stop .48 maybe sopositioned as to be engaged byithe projecting lug 41 on the master door. asit pivots-about the-hinge pin Hi to actuate the .connectorAZ ,and'the latch bars 26 towards the right as shown to thBilOCkEd position when the master door- 1 8,-is closed, and-prevent-closure of the masterdoor l;8iby;interfering with the lug 41 until the ;latch;bars 2612f a1l of the latch mechanisms are :actuated to a free .position by the closure of their respective sub=doors. 'In order to permit thevlatch bars 225 .to beindividually actuated to thefi'ee position, they may be pivotallyconnected to each other, and the latch bar for the sub-door in Figs. 1 and 5.

key-operated .or otherwise.

l6 may be piovtally connected to the connector izby means of hingedjoints 50.

When the master door is and sub-doors l5 and [B are in the open position, as shown in Fig. 1,

the connector 42 is biased toward the left by means of the spring 46, and the lock pins 33 are withdrawn so as to be free of the keepers 38. Underthese conditions, the latch bars 26 are in 'theirppenposition and the depending stops 36 interferewiththezlower inturned end portions 32 of the supportbrackets 30, looking the latch bars in this position. The master door l8 cannot be closed-underthese circumstances since the projecting lug 41 on the door l8 interferes with the stop member 48 of the connector 42, which is prevented "from moving to the right.

When-thesub-doorsand themaster door are in the openposition, .thelatch mechanisms of the lock pins 33 of the latch bars 26 are thus actuated into the openings 39 of the door lock members as shown in Figs. 3 and 6,to lock the subdoors.

The master'door l8 may then be locked by operating the key operated lock device 20, and the key 2! removed-to operate an associated lock mechanism, or the'like (not shown).

.When the sub-doors and the master door are thus locked-thesub-doors cannot be opened until the master door :I 8 is first opened, permitting the connector 42 to actuate the latch bars 26 to the open position.

From the abovedescription and accompanying drawing it .will be-apparent that we have provided in a simple and effective manner for interlocking the operation of a-pluralityof sub-doors with a master door, which may in turn be interlocked with associated switching apparatus, such as disconnectswitches, circuit breakers, or the like, by

meanstof anyrsuitablelock device, cam-operated, The sub-doors and master door may be opened and closed only in a predetermined sequence; since the. sub-doors cannot be opened until the master door is first opened and the master door cannot-beclosed-until the sub-doors:are;firs.t allgclosed, whereupon ,theyare simultaneously,lockedbythe closing of the master door. Suchaan: interlock systemis simple to construct, isipositiveand foolproof inoperation, and

requires but ,asingle ,lock-device-for the master doortointerlock theoperation of all the-doors with the associatedapparatua I Since different embodiments of the invention maybemade anddenartures may ;be made from the particular description thereof, :yet still be within-thescope of :the invention, it is intended that all the matter contained. in the a ve description' or shown in:the accompanying drawing shall .be considered asillustrative and not in a limiting sense.

:We claim as. cur-invention:

l. .A latch mechanism :for a sub-door .and a .rnaster door comprising, iailatch memberforzlockmg :the :subadoor in the closed position, :connecting means for actuating the latch member, means to bias the connecting means to the open position to free the sub-door when the master door is opened, and operating means to actuate the connecting means in response to'closure of the master door and prevent closing of the master door while the sub-door is open.

2. An interlocking latch mechanism for a subdoor positioned adjacent a master door comprising, a latch member operable to lock the subc'ioor, means to lock the latch member in the open position, means responsive to closure of the subdoor to free the latch member, and means responsive to closure of the master door to operate the latch member only when the sub-door is closed first.

3. A latch mechanism for a master door having a lock device and a plurality of associated doors positioned in side-by-side relation comprising, means operable in the open position to prevent closure of the master door said means being also responsive to movement of the master door to simultaneously lock the associated doors, means for retaining the aforesaid means in the open position, and additional means operatively connected to the associated doors operable only when all the associated doors are closed to release the first-mentioned means.

4. A latch system for a master door having a lock device and a plurality of associated doors comprising, a plurality of locking means actuable to lock the associated doors in the closed position in response to closure of the master door, means effective to prevent actuation of the locking means, and means responsive to the closure of the associated doors to render the last mentioned means ineffective and permit closure of the master door only when all of the associated doors are first closed.

5. An interlock system for a master door and a plurality of sub-doors to be interlocked therewith comprising, a lock member movably supported adjacent each sub-door, means on each sub-door cooperative with the lock member in the closed position to prevent opening of the sub-door, means for operating the lock members in unison, means preventing operation of the lock members while any one of the sub-doors is open, and means actuated by the master door cooperating with the lock members to prevent closure of the master door while any one of the sub-doors is open.

6. An interlock system for a plurality of subdoors and a master door comprising, a plurality of operatively connected latch members having lock pins for each of the sub-doors, means associated with each sub-door to lock each latch member in the open position, means connected with each sub-door disposed to actuate its latch member to a free position only when the subdoor is closed, and means operatively connecting the latch members to the master door to permit rality of pivotally connected latch bars supported on the frame of the enclosures adjacent the subdoors, a latch pin carried by each latch bar, means for locking each of the latch bars in the open position, means on each sub-door to actuate its associated latch bar to a free position, and means associated with the master door and the latch bars preventing closure of the master door until all of the sub-doors have been closed.

8. An interlock system for a plurality of subdoors and a master door comprising, a plurality of pivotally connected latch bars slidably supported adjacent the sub-doors, a latch pin actuated by each latch bar to lock the associated subdoor in the closed position, means on each latch bar to lock said latch bar in the open position, means operable on the closure of each sub-door to free the associated latch bar from the open position, and means to actuate the latch barsto the closed position when freed in response to closure of the master door.

9. A latch mechanism for a plurality of subdoors to be opened and closed in a predetermined sequence relative to a master door comprising, a latch member for each sub-door actuable to open and closed positions, means to lock each latch member in the open position, means actuable in response to closure of each sub-door to render the aforesaid means ineffective, and operating means connected to the latch members effective only when all of the first-mentioned means are rendered ineffective to actuate the latch members to the closed position in response to closure of the master door.

10. An interlock system for an enclosure subdoor and a master door having an independently operated lock device comprising, a slidable latch bar supported adjacent the sub-door with a lock pin secured thereto and a depending projection disposed to interfere with means on the frame of the enclosure to lock the latch bar in the open position, a projecting lug on the sub-door having an inclined upper surface portion effective to raise the latch bar to a free position so that the projection clears the means on the frame when the sub-door is closed and a recess to receive the lock pin, a slidable operating member operatively connected to the latch bar, and means actuated by the master door to actuate the latch bar to the closed position and prevent closure of the master door before the latch bar is in the free position.

11. An interlock system for a plurality of subdoors disposed to be opened and closed in predetermined sequence relative to a master door comprising, a plurality of pivotally connected latch members slidably supported adjacent the sub-doors having lock pins secured thereto and projecting stop members disposed to interfere with a stationary member to lock the latch members in the open position, means on each subdoor operable to actuate its associated latch member to free the stop member when the subdoor is closed, a connecting member operatively connected to one of the latch members, and means secured to the master door to engage the connecting member to operate the latch members to the closed position.

GLEN L. CLAYBOURN. LLOYD E. KECK. 

